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GlossaryRoles

ML engineer

The one who trains a model and keeps it in service

An ML engineer takes a known learning method and makes it work on one organisation’s data, all the way to production, like an engineer building a bridge with a proven technique.

  • Floor 1The Model
  • P4Writes the model
  • Established titleIt has been in adverts long enough to mean something.

What they answer for

The deliverable

A model trained on real data, served to users, with its drift watched. If they leave, a service degrades without anything stopping.

The profile

Five activities, scored 0 to 3
  • ResearchProducing knowledge that does not yet exist.
  • BuildShipping a system that runs, deploys and breaks.
  • OperateKeeping it in production: cost, incidents, drift, on-call.
  • VerifyMeasuring, testing, attacking. Producing a verdict that holds.
  • LeadDeciding, persuading, driving adoption, answering to others.

What the work is

The method already exists

The difference from research fits in one sentence: the method already exists, in a paper or in a library. What remains is no simpler, but it is something else: getting the data, cleaning it, training, measuring, serving, and watching what degrades.

What actually costs

What actually costs is almost never the model. It is the data: where it came from, the right to use it, its quality, and the fact that it shifts underneath the service while the service runs. A model that loses five points in six months was not trained badly; it was trained on a world that moved.

The trap

The trap is the confusion with the AI engineer, sustained by adverts because the second title pays better. One question settles it: do you train here, or do you borrow? An advert asking for both describes two posts, and you will only hold one.

A week in the role

  • Data pipelines: collection, cleaning, the split between training and test.
  • Training runs, and above all the waiting they involve, during which you prepare the next one.
  • Measurement: what gained, what lost, and on which population.
  • Monitoring: drift shows up over weeks, never in a unit test.

Ways in

  • From software development with training in machine learning, which is the commonest route.
  • From data science, accepting that you answer for a service and no longer for a conclusion.
  • What the role does not require, whatever the advert says: a doctorate.

Reading an advert

2 signs
The advert mentions training and large language models in the same sentence.
Almost nobody trains a large language model. This means fine-tuning, or an AI engineer post under the wrong name.
Nothing is said about where the data comes from.
That is the real subject of the trade, and the first thing that stalls a project. An advert silent on it has not met the problem yet.

Terms to know

4 entries

fine-tuningtraining datainferencebias

Neighbouring roles

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